To achieve a high service level reliability goal (e.g. 99.999%) in an integrated cloud environment, redundant service nodes are necessary. Redundancies may be achieved with a variety of topologies (also referred to as N:K topologies). Allocating Customers to a virtual Trunking Session Border Controller (vTSBC) in an integrated cloud environment has serious limitations. The integrated cloud environment, being new, does not have the high service level reliability required of a service-provider. To increase service-reliability, the network operator may add additional capacity which leads to excessive over-provisioning. Additionally, only single-failure scenarios are typically entertained. Now with integrated cloud as the environment of choice, a double-failure scenario must be considered. However, as time progresses the reliability of integrated cloud will increase. At that time, the solution proposed, will facilitate moving customers from a double to single failure topology.
There is a need to reduce the over-provisioned capacity, and to increase service reliability, and topological flexibility when allocating customers to network element. There is also a need to provide an allocation of customers that tolerates single or double failure scenarios, and that allows moving between these two scenarios transparently (from a customer's point of view). There is also a need to adjust customer allocation capacity via topology changes.